<template>
  <div class="head-container">
    <el-breadcrumb class="el-breadcrumb" separator="/">
      <transition-group name="breadcrumb">
        <el-breadcrumb-item v-show="breadcrumbReturn" key="back">
          <el-button type="text" icon="el-icon-caret-left"  @click="goBack()" size="small">返回</el-button>
        </el-breadcrumb-item>
        <el-breadcrumb-item v-for="(item,index) in levelList" v-if="item.meta.title" :key="item.path">
        <span v-if="item.redirect==='noredirect'||index==levelList.length-1"
              class="no-redirect">{{ item.meta.title }}</span>
          <a v-else @click.prevent="handleLink(item)">{{ item.meta.title }}</a>
        </el-breadcrumb-item>
      </transition-group>
    </el-breadcrumb>
  </div>
</template>

<script>
  import pathToRegexp from 'path-to-regexp'

  export default {
    data() {
      return {
        levelList: null,
        breadcrumbReturn: false
      }
    },
    watch: {
      $route() {
        this.getBreadcrumb()
      }
    },
    created() {
      this.getBreadcrumb()
    },
    methods: {
      getBreadcrumb() {
        this.breadcrumbReturn = this.$route.meta.breadcrumbReturn
        let matched = this.$route.matched.filter(item => {
          if (item.name && item.path) {
            return true
          }
        })
        const first = matched[0]
        if (first && first.name !== this.$store.state.app.breadcrumb.name && matched.length!==1) {
          matched = [{ path: this.$store.state.app.breadcrumb.path, meta: { title: this.$store.state.app.breadcrumb.title} }].concat(matched)
        }else{
          this.$store.dispatch('breadcrumb', first)
        }
        this.levelList = matched
      },
      pathCompile(path) {
        // To solve this problem https://github.com/PanJiaChen/vue-element-admin/issues/561
        const { params } = this.$route
        const toPath = pathToRegexp.compile(path)
        return toPath(params)
      },
      handleLink(item) {
        const { redirect, path } = item
        if (redirect) {
          this.$router.push(redirect)
          return
        }
        this.$router.push(this.pathCompile(path))
      },
      goBack() {
        this.$router.go(-1)
      }
    }
  }
</script>

<style rel="stylesheet/scss" lang="scss" scoped>
  .app-breadcrumb.el-breadcrumb {
    display: inline-block;
    font-size: 14px;
    line-height: 50px;
    margin-left: 10px;

    .no-redirect {
      color: #97a8be;
      cursor: text;
    }

    .back {
      margin-right: 3px;
      font-weight: bold;
      font-family: "simsun";
      color: #777
    }
  }
</style>
